1 files changed, 100 insertions, 0 deletions
diff --git a/devtools/server/actors/resources/sources.js b/devtools/server/actors/resources/sources.js
new file mode 100644
index 0000000000..6b3ab1d5e1
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+++ b/devtools/server/actors/resources/sources.js
@@ -0,0 +1,100 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const {
+  TYPES: { SOURCE },
+} = require("resource://devtools/server/actors/resources/index.js");
+const Targets = require("resource://devtools/server/actors/targets/index.js");
+
+const {
+  STATES: THREAD_STATES,
+} = require("resource://devtools/server/actors/thread.js");
+
+/**
+ * Start watching for all JS sources related to a given Target Actor.
+ * This will notify about existing sources, but also the ones created in future.
+ *
+ * @param TargetActor targetActor
+ *        The target actor from which we should observe sources
+ * @param Object options
+ *        Dictionary object with following attributes:
+ *        - onAvailable: mandatory function
+ *          This will be called for each resource.
+ */
+class SourceWatcher {
+  constructor() {
+    this.onNewSource = this.onNewSource.bind(this);
+  }
+
+  async watch(targetActor, { onAvailable }) {
+    // When debugging the whole browser, we instantiate both content process and browsing context targets.
+    // But sources will only be debugged the content process target, even browsing context sources.
+    if (
+      targetActor.sessionContext.type == "all" &&
+      targetActor.targetType === Targets.TYPES.FRAME &&
+      targetActor.typeName != "parentProcessTarget"
+    ) {
+      return;
+    }
+
+    const { threadActor } = targetActor;
+    this.sourcesManager = targetActor.sourcesManager;
+    this.onAvailable = onAvailable;
+
+    // Disable `ThreadActor.newSource` RDP event in order to avoid unnecessary traffic
+    threadActor.disableNewSourceEvents();
+
+    threadActor.sourcesManager.on("newSource", this.onNewSource);
+
+    // For WindowGlobal, Content process and Service Worker targets,
+    // the thread actor is fully managed by the server codebase.
+    // For these targets, the actor should be "attached" (initialized) right away in order
+    // to start observing the sources.
+    //
+    // For regular and shared Workers, the thread actor is still managed by the client.
+    // The client will call `attach` (bug 1691986) later, which will also resume worker execution.
+    const isTargetCreation = threadActor.state == THREAD_STATES.DETACHED;
+    const { targetType } = targetActor;
+    if (
+      isTargetCreation &&
+      targetType != Targets.TYPES.WORKER &&
+      targetType != Targets.TYPES.SHARED_WORKER
+    ) {
+      await threadActor.attach({});
+    }
+
+    // Before fetching all sources, process existing ones.
+    // The ThreadActor is already up and running before this code runs
+    // and have sources already registered and for which newSource event already fired.
+    onAvailable(
+      threadActor.sourcesManager.iter().map(s => {
+        const resource = s.form();
+        resource.resourceType = SOURCE;
+        return resource;
+      })
+    );
+
+    // Requesting all sources should end up emitting newSource on threadActor.sourcesManager
+    threadActor.addAllSources();
+  }
+
+  /**
+   * Stop watching for sources
+   */
+  destroy() {
+    if (this.sourcesManager) {
+      this.sourcesManager.off("newSource", this.onNewSource);
+    }
+  }
+
+  onNewSource(source) {
+    const resource = source.form();
+    resource.resourceType = SOURCE;
+    this.onAvailable([resource]);
+  }
+}
+
+module.exports = SourceWatcher;